The invention relates generally to liquid level sensors, and more particularly to those for controlling an alarm pressure fluid supply responsive to changes of liquid level in a pressure vessel.
A search of the prior art disclosed the following references: B. E. Shaw, U.S. Pat. No. 2,322,166 for Air Volume Control; W. B. Nold, U.S. Pat. No. 2,022,430 for Valve and Float; and J. L. Garske, U.S. Pat. No. 2,176,494 for a Ball Cock.
Shaw teaches an air pressure control device for a hydropneumatic system in which a pressure tank water-level is float monitored to release a spring pressured relief valve to open when water level is low and tank pressure is higher than the spring pressure keeping the relief valve closed.
Nold teaches a combination float and hand controlled valve for regulating compressed liquid refrigerant from the compressive side to the cumulator side of the system.
Garske teaches a float controlled valve in a flush tank that is assisted in closing the pressure water supply thereto by the pressure of the supplied water.
The invention teaches a liquid level sensor mounted on the side of a pressure vessel. A two part mechanical linkage is mounted in and extends through an otherwise closes sensor end and an aperture in the vessel side and connects with a vessel float for sensing changes in liquid level from a predetermined base level to actuate, with no pressure interchange or release, a poppet valve slidably mounted in a part of the mechanical linkage mounted in the sensor to release an alarm flow of pressure fluid supply from an outside source. A change of 180 degrees in mounting the poppet valve changes the sensor from acting as a falling liquid sensor to a rising level liquid sensor.